Hvad circadian tracker (phi+)

ABSTRACT

A method of detecting a disruption in a diurnal rhythm of a patient having an implantable blood pump comprising calculating a moving average convergence divergence (MACD) based on power consumed by the implantable blood pump to maintain a constant rotational speed of an impeller of the implantable blood pump and generating an alert when the calculated MACD does not cross a MACD zero line for a predetermined MACD zero line crossing time threshold.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims priority to patentapplication Ser. No. 15/648735, filed Jul. 13, 2017, the entirety of allof which is incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

n/a

TECHNICAL FIELD

The present invention relates to a method and system for detecting adisruption in a diurnal rhythm of a patient having an implantable bloodpump.

BACKGROUND

Ventricular assist devices, or VADs, are lifesaving mechanicalcirculatory support devices, or MCSDs, configured to assist the heart inpumping blood throughout the body. VADs may include centrifugal pumps,axial pumps, or other kinds electromagnetic pumps configured to pumpblood from the heart to blood vessels to circulate around the body. Onesuch centrifugal pump is the HVAD sold by HeartWare, Inc. and is shownand described in U.S. Pat. No. 7,997,854 the entirety of which isincorporated by reference. One such axial pump is the MVAD sold byHeartWare, Inc. and is shown and described in U.S. Pat. No. 8,419,609the entirety of which is incorporated herein by reference.

Detecting patient adverse events associated with the implantation ofVADs is challenging owing to the fact that patients requiring suchdevices often have different cardiac pathology that necessitated theimplantation of the VAD within the patient. One solution devised is toimplant sensors into or onto the VAD to detect operating parameters ofthe blood pump. Implanting sensors within or onto VADS, however,requires sensor calibration, are subject to potential failure fromcorrosion or other events, and increases the power necessary to operatethe VAD.

SUMMARY

A system of one or more computers can be configured to performparticular operations or actions by virtue of having software, firmware,hardware, or a combination of them installed on the system that inoperation causes or cause the system to perform the actions. One or morecomputer programs can be configured to perform particular operations oractions by virtue of including instructions that, when executed by dataprocessing apparatus, cause the apparatus to perform the actions. Onegeneral aspect includes a method of detecting a disruption in a diurnalrhythm of a patient having an implantable blood pump, including:calculating a moving average convergence divergence (MACD) based onpower consumed by the implantable blood pump to maintain a constantrotational speed of an impeller of the implantable blood pump; andgenerating an alert when the calculated MACD does not cross a MACD zeroline for a predetermined MACD zero line crossing time threshold. Otherembodiments of this aspect include corresponding computer systems,apparatus, and computer programs recorded on one or more computerstorage devices, each configured to perform the actions of the methods.

Implementations may include one or more of the following features. Themethod where the MACD zero line crossing time threshold is 24 hours. Themethod where calculating the MACD includes calculating a slow movingaverage (SMA), and where the SMA is a one second average measurement ofthe power consumed by the implantable blood measured at a predeterminedinterval for a first predetermined period of time. The method where thepredetermined interval is 15 minutes. The method where the firstpredetermined period of time is 48 hours. The method where calculatingthe MACD includes calculating a fast moving average (FMA), and where theFMA is a one second average measurement of the power consumed by theimplantable blood measured at the predetermined interval for a secondpredetermined period of time less the first period of time. The methodwhere the second predetermined period of time is four hours. The methodwhere the patient has a diurnal cycle, and where generating the alert isindicative of a loss of the patient's diurnal cycle. The method wherethe method further includes correlating the loss of the patient'sdiurnal cycle to at least one from the group including of thrombus andtachycardia. The method generating an alert includes at least one fromgroup including of sounding an alarm on a controller of the implantableblood pump and displaying a time and date of the alert in a log file ofa controller of the implantable blood pump. Implementations of thedescribed techniques may include hardware, a method or process, orcomputer software on a computer-accessible medium.

One general aspect includes a system of detecting a disruption in adiurnal rhythm of a patient having an implantable blood pump, including:a controller having a processor, the controller being in communicationwith the implantable blood pump and a power source configured to providepower to the implantable blood pump, the controller being configured tocalculate a moving average convergence divergence (MACD) based on powerconsumed by the implantable blood pump to maintain a constant rotationalspeed of an impeller of the implantable blood pump; and generate analert when the calculated MACD does not cross a MACD zero line for apredetermined MACD zero line crossing time threshold. Other embodimentsof this aspect include corresponding computer systems, apparatus, andcomputer programs recorded on one or more computer storage devices, eachconfigured to perform the actions of the methods.

Implementations may include one or more of the following features. Thesystem where the MACD zero line crossing time threshold is 24 hours. Thesystem where calculating the MACD includes calculating a slow movingaverage (SMA), and where the SMA is a one second average measurement ofthe power consumed by the implantable blood measured at a predeterminedinterval for a first predetermined period of time. The system where thepredetermined interval is 15 minutes. The system where the firstpredetermined period of time is 48 hours. The system where calculatingthe MACD includes calculating a fast moving average (FMA), and where theFMA is a one second average measurement of the power consumed by theimplantable blood measured at the predetermined interval for a secondpredetermined period of time less the first period of time. The systemwhere the second predetermined period of time is four hours. The systemgenerating an alert includes at least one from group including ofsounding an alarm on a controller of the implantable blood pump anddisplaying a time and date of the alert on a display of a controller ofthe implantable blood pump. The system where the controller is furtherconfigured to clear the alert when the calculated MACD crosses the MACDzero line for the predetermined MACD zero line crossing time threshold.Implementations of the described techniques may include hardware, amethod or process, or computer software on a computer-accessible medium.

One general aspect includes a method of detecting a disruption in adiurnal rhythm of a patient having an implantable blood pump and adiurnal cycle, including: calculating a moving average convergencedivergence (MACD) based on power consumed by the implantable blood pumpto maintain a constant rotational speed of an impeller of theimplantable blood pump. The method also includes generating an alertwhen the calculated MACD does not cross a MACD zero line for apredetermined MACD zero line crossing time threshold, the alert beingindicative of a loss of the patient's diurnal cycle, the generating analert includes at least one from group including of sounding an alarm ona controller of the implantable blood pump and displaying a time anddate of the alert in a log file of a controller of the implantable bloodpump. The method also includes correlating the loss of the patient'sdiurnal cycle to at least one from the group including of thrombus andtachycardia. The method also includes clearing the alert when thecalculated MACD crosses the MACD zero line for the predetermined MACDzero line crossing time threshold. Other embodiments of this aspectinclude corresponding computer systems, apparatus, and computer programsrecorded on one or more computer storage devices, each configured toperform the actions of the methods.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is an exemplary display of a log file of an implantable bloodpump operating within normal parameters;

FIG. 2 is an exemplary flow chart showing a method of determining adisruption in circadian rhythm in a patient with an operating blood pumpin accordance with the present application;

FIG. 3 is an exemplary display of a log file of an implantable bloodpump operating within normal parameters;

FIG. 4 is the log file of FIG. 3 with an MACD calculation displayed overa two-day period and operating within normal parameters;

FIG. 5 is an exemplary display of a log file of an implantable bloodpump operating abnormally;

FIG. 6 is the log file of FIG. 5 with an MACD calculation displayedindicating a loss of circadian rhythm;

FIG. 7 is an exemplary display of a log file of an implantable bloodpump operating abnormally;

FIG. 8 is the log file of FIG. 7 with an MACD calculation displayedindicating the presence of thrombus;

FIG. 9 is an exemplary display of a log file of an implantable bloodpump operating abnormally; and

FIG. 10 is the log file of FIG. 9 with an MACD calculation displayedindicating the presence of ventricular tachycardia.

DETAILED DESCRIPTION

Referring now to the drawings in which like reference designators referto like elements, there is shown in FIG. 1 a controller 10 and anexemplary log file 12 constructed in accordance with the principles ofthe present application. The controller 10 may include a processorhaving processing circuity configured to measure parameters of a bloodpump implanted within a human or animal patient and to control theoperation of the implantable blood pump. As used herein, an implantableblood pump refers to any MCSD, such as HVAD, and MVAD, having movableelement, such as impeller, configured to pump blood from the heart tothe patient's circulatory system. The controller 10 be may incommunication with the implantable blood pump through one or moreconductors (not shown) and measures parameters such as flow rate out ofthe pump in mL/pin, power consumption in mWatts, and the rotationalspeed of the impeller in RPM. The controller 10 is configured to measurea one second average these parameters at a predetermined interval andrecord these parameters in controller log files 12 stored in thecontroller 10. For example, in the log file 12 shown in FIG. 1, thecontroller 10 averages flow rate, power, and speed of the impeller byaverage the measurement of each parameter over a one second intervalevery 15 minutes and records the same on the log file 12 which can bedisplayed in graphical form on a computer as shown in the exemplary logfile 12 in FIG. 1. The 15 minute interval may be variable as well as theone second average. For example, it is fully contemplated that anyinterval, for example, 1-60 minutes may be used to sample the measuredparameters from the blood pump and the average may be over, for example,1-5 seconds. Measuring the one second average of the measured parametersevery 15 min helps to reduce noise in the log file 12.

Referring now to FIG. 2, the controller 10 is further configured tocalculate a moving average convergence divergence (MACD) based on powerconsumed by the implantable blood pump to maintain a constant rotationalspeed of an impeller of the implantable blood pump. As used here, theMACD refers a trend-following indicator that shows the relationshipbetween two moving averages of the same parameter. In the exemplaryembodiment shown in FIG. 2, calculating the MACD includes calculating aslow moving average (SMA) and a fast moving average (FMA). The SMA is aone second average measurement of the power consumed by the implantableblood measured at a predetermined interval for a first predeterminedperiod of time. In an exemplary configuration, the predeterminedinterval for the SMA is 15 minutes and the first predetermined period oftime of 48 hours. In other configurations, the first predeterminedperiod of time maybe be longer or shorter than 48 hours. The FMA is aone second average measurement of the power consumed by the implantableblood measured at the predetermined interval for a second predeterminedperiod of time less the first period of time. For example, the FMA maybe calculated over the predetermined interval of 15 minutes and forsecond period of time of four hours. The MACD is calculated bysubtracting the SMA from FMA to create an index showing trends in powerconsumed by the implantable blood pump.

Continuing to refer to FIG. 2, when the calculated MACD does not cross aMACD zero line for a predetermined MACD zero line crossing timethreshold an alert is generated. For example, while the calculated MACDmay vary in amplitude, mean level, and rhythmic and non-rhythmiccomponents, if the MACD level does not cross the zero line during acrossing time threshold, for example, 24 hours, it is indicative of aloss in a patient's diurnal rhythm. Because the MACD compares to movingaverages, namely, the SMA and FMA, the reference is based on a zero,i.e. either the FMA is above the MACD will be above zero when the FMA isgreater than the SMA and below zero when the FMA is less than the SMA.However, in a patient having a normal diurnal cycle, the MACD shouldcross the zero line at least once every 24 hours. When the calculatedMACD does not cross a MACD zero line for the predetermined MACD zeroline crossing time threshold an alert is generated and the patient'sdiurnal cycle has been interrupted or lost. The alert may includesounding an alarm on the controller 10 of the implantable blood pumpand/or displaying a time and date of the alert in a log file 12 of thecontroller 10. The alert may further include flagging in the log filethe 24 hour period or more than one 24 hour period in which the MACDcalculation does not cross the zero line. For example, the log file 12when displayed on a computer, may mark the 24 hours periods in which nozero crossings have occurred in a different color than the backgrounddisplay for easy recognition. The controller 10 and/or the physicianreviewing the log files 12 may correlate the loss of the patient'sdiurnal cycle to adverse events such as thrombus, tachycardia,arrhythmia, and GI bleeding. The alert may be cleared the alert when thecalculated MACD crosses the MACD zero line for the predetermined MACDzero line crossing time threshold. For example. If the MACD crosses thezero line, the shaded area or otherwise flagged area of log file isremoved indicating normal operation for that time period.

Referring now to FIGS. 3 and 4, in this exemplary log file 12 of apatient whose pump is operating in homeostasis, the MACD is displayedabove the SMA and FMA trends line (FIG. 4) and shows a smooth trend linewhere power increases during that day and decreases at night. The MACDfurther crosses the zero line at least once every 24 hours. Suchcrossings are indicated by a bullet point or other indicia such thatthey are readily visible on the log file. For example, as shown in FIG.4, between Apr. 10, 2017 and Apr. 12, 2017, the MACD crosses thezero-line five times. Thus, in this exemplary log file 12 no alert wasgenerated and there is no indication of adverse events.

Referring now to FIGS. 5 and 6, in this exemplary log file 12 of apatient whose pump is operating is not operating homeostasis, the MACDis displayed above the SMA trend line (FIG. 6). Between Oct. 1, 2016 andOct. 14, 2016, the MACD crosses the zero-line at least once every 24hours as indicated by the bullets on the MACD trend line atzero-crossings. However, beginning about Oct. 14, 2016, at least one 24hour period of no zero-crossings begin in which the MACD trend linestays below zero. The controller 10 shades the area in which nozero-crossings occur for at least 24 hours such that the physician candetermine when the disruption in homeostasis of the blood pump occurredand for how long it lasted. In this particular example, the lack ofzero-crossings for four consecutive days is indicative in the loss ofthe patient's circadian rhythm.

Referring now to FIGS. 7 and 8, in this exemplary log file 12 of apatient whose pump is operating is not operating homeostasis, the MACDis displayed above the SMA trend line (FIG. 8). The log file indicatesthat between Apr. 07, 2017 and Apr. 23, 2017, there are multiple periodsof time in which the MACD trend line include no zero-crossings for aperiod of at least 24 hour following by periods in which the MACD trendline returns to normal. The controller 10 shades the area in which nozero-crossings occur for at least 24 hours such that the physician candetermine when the disruption in homeostasis of the blood pump occurredand for how long it lasted. In this particular example, the periodiclack of zero-crossings and/or the increase in the MACD trend linefollowing about Apr. 21, 2017 is indicative of thrombus.

Referring now to FIGS. 9 and 10, in this exemplary log file 12 of apatient whose pump is operating is not operating homeostasis, the MACDis displayed above the SMA trend line (FIG. 10). The log file indicatesthat between Mar. 28, 2017 and Mar. 31, 2017 and between Apr. 1, 2017and Apr. 4, 2017, there periods of time in which the MACD trend lineinclude no zero-crossings for a period of at least 24 hour following byperiods in which the MACD trend line returns to normal. The controller10 shades the area in which no zero-crossings occur for at least 24hours such that the physician can determine when the disruption inhomeostasis of the blood pump occurred and for how long it lasted. Inthis particular example, the periodic lack of zero-crossings with aperiod of rapid zero-crossings is indicative of ventricular tachycardia.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings without departing from the scope andspirit of the invention, which is limited only by the following claims.

What is claimed is:
 1. A method of detecting a disruption of a diurnalrhythm of a patient having an implantable blood pump, comprising:calculating a moving average convergence divergence (MACD) based onpower consumed by the implantable blood pump to maintain a constantrotational speed of an impeller of the implantable blood pump; recordingthe calculated MACD in a log file; and correlating when the calculatedMACD does not cross a MACD zero line for a predetermined MACD zero linecrossing time threshold to a disruption of the patient's diurnal rhythm.2. The method of claim 1, wherein the MACD zero line crossing timethreshold is 24 hours.
 3. The method of claim 1, wherein calculating theMACD includes calculating a slow moving average (SMA), and wherein theSMA is a one second average measurement of the power consumed by theimplantable blood measured at a predetermined interval for a firstpredetermined period of time.
 4. The method of claim 3, wherein thepredetermined interval is 15 minutes.
 5. The method of claim 4, whereinthe first predetermined period of time is 48 hours.
 6. The method ofclaim 3, wherein calculating the MACD includes calculating a fast movingaverage (FMA), and wherein the FMA is a one second average measurementof the power consumed by the implantable blood measured at thepredetermined interval for a second predetermined period of time lessthe first period of time.
 7. The method of claim 6, wherein the secondpredetermined period of time is four hours.
 8. The method of claim 1,wherein the method further includes correlating the disruption of thepatient's diurnal rhythm to at least one from the group consisting ofthrombus and tachycardia.
 9. A system of detecting a disruption in adiurnal rhythm of a patient having an implantable blood pump,comprising: a controller having a processor, the controller being incommunication with the implantable blood pump and a power sourceconfigured to provide power to the implantable blood pump, thecontroller being configured to: calculate a moving average convergencedivergence (MACD) based on power consumed by the implantable blood pumpto maintain a constant rotational speed of an impeller of theimplantable blood pump; and correlate when the calculated MACD does notcross a MACD zero line for a predetermined MACD zero line crossing timethreshold to a disruption of the patient's diurnal rhythm.
 10. Thesystem of claim 9, wherein the MACD zero line crossing time threshold is24 hours.
 11. The system of claim 9, wherein calculating the MACDincludes calculating a slow moving average (SMA), and wherein the SMA isa one second average measurement of the power consumed by theimplantable blood measured at a predetermined interval for a firstpredetermined period of time.
 12. The system of claim 11, wherein thepredetermined interval is 15 minutes.
 13. The system of claim 12,wherein the first predetermined period of time is 48 hours.
 14. Thesystem of claim 11, wherein calculating the MACD includes calculating afast moving average (FMA), and wherein the FMA is a one second averagemeasurement of the power consumed by the implantable blood measured atthe predetermined interval for a second predetermined period of timeless the first period of time.
 15. The system of claim 14, wherein thesecond predetermined period of time is four hours.
 16. A method ofdetecting a disruption of a diurnal rhythm of a patient having animplantable blood pump and a diurnal cycle, comprising: calculating amoving average convergence divergence (MACD) based on power consumed bythe implantable blood pump to maintain a constant rotational speed of animpeller of the implantable blood pump; and displaying the calculatedMACD in a log file; correlating when the calculated MACD does not crossa MACD zero line for a predetermined MACD zero line crossing timethreshold to a disruption of the patient's diurnal rhythm; andcorrelating the disruption of the patient's diurnal rhythm to at leastone from the group consisting of thrombus and tachycardia.